The invention relates to a method of manufacturing a microdialysis catheter to be inserted into and guided by a blood vessel of a living being.
Microdialysis is used to monitor the interstitial fluid in various body organs with respect to local metabolic changes. To perform Microdialysis, a catheter is used including an elongate flexible body having at least two internal channels therealong, and, at its distal end, a dialysis chamber. U.S. Pat. No. 4,694,832 to Ungerstedt discloses a dialysis probe provided in a distal end of an elongate, flexible hose. The probe consists of several elements that have to be carefully assembled and mounted at a free end of the hose during manufacture of the microdialysis catheter. This involves a substantial risk that the various elements come loose when the catheter is in use. Furthermore, the brittle microdialysis membrane is not internally supported well enough to make this known microdialysis probe suitable for insertion into and guidance by a blood vessel, mounted in the end of the flexible hose.
It is an object of the invention to set aside these drawbacks by proposing a method of manufacturing a microdialysis catheter that is robust, simple to insert in a vessel, and has a simple construction.
According to the present invention there is provided a method of manufacturing a microdialysis catheter, comprising the steps of extruding a flexible material to form an elongate catheter body having a substantially cylindrical outer surface and a plurality of continuous internal channels extending in the longitudinal direction of said catheter body; sealing a free end of said catheter body; providing in said surface at a distance from said free end an opening extending into said catheter body to communicate with a portion of a first of said channels; providing communication between said first channel and a second of said channels at a distance from said free end shorter that said distance; and covering said opening by a microdialysis membrane.